Improved safety-fuse



y Nirnn rares Armar muon.

JOHN H. ANDREVS, OF AVON, OOINEOTIOUT.

IMPROVED SAFETY-FUSE.

Specification forming part of Letters Patent No. 45,572, dated December 27, 1864.

fuse in America except my own, and the rarity of the art renders it proper to explain briefly the ordinary fuse of this character. In the common mode of manufacturing these fuses, several yarns of cotton, jute, linen, or other fibrous material are twisted together Vto form 4the main substance ofthe fuse, and a train of powder is inclosed in its center, the train being so slender and so inelosed as to burn slowly and uniformly. The powder is introduced between the several strands of fibrous material by the aid of a funnel-shaped tube having a small aperture at its lower extremity. The whole is then cross-wound with iiner yarns of cotton or other fibrous material, and the surface afterward further protected. This mode of construction fulfills, with some success, the conditions required, which are not alone the preservation of a series of grains of powder in juxtaposition Yeach with another along the center of the structure, and the preservation thereof in a dry condition, but also that the combustion, as it proceeds, shall so far destroy the enveloping material as to maintain a tolerably free escape for the gases, so that the powder shall burn with uniformity from one end to the other. A fine center thread is usually led down through the powder-funnel, and allowed to remain in the fuse with the powder. This tends greatly to reduce the risk that the powder may clog in the passage; but accidental accumulations of detached particles of fibrous material from the center thread, the existence of uneven places in the outer yarns, with various other causes, frequently occasion a partial or entire interruption of the powder as it is being twisted into the yarns. This is a very serious evil, aslit not only renders the fuse at that point inoperative -and worthless, but causes it to' become a source of great delay and expense to those attempting to use the article. Somctimes'fuse so defective retains fire smouldering slowly within it until it again ignites the train and endangers the lives ofthe workmen. To obviate this difficulty I first inclose the powder in a slender tube of paper or other suitable material by passing a strip or several strips into the powder-tube near its lower extremity and folding or bending the same around the powder. By thus'surround-- ing and smoothly inclosing the powder before it leaves the funnel, Isecure a more continuous and uniform line of powder, and conse quently secure more certainty in its burning and more regularity in its rate of consumption. It also affords very favorable conditions for introducing a water-proof coating1 near the center of the fuse.

The common water-proof fuses," known as single-tape,77 double-tape,77 and tripletape77 fuses, are made by winding the outer surface spirally with strips of cloth or tape, or the warp-yarns thereof' correspondingly aggregated together. The common fuse, with its envelope of' jute or the like, above described, is coated with fuse-varnish a-nd dried,and `then run through a winding-machine, in which flf^\ tape or its equivalent is wound tightly around,

slightly lapping or superposing each coil external protections is chieiiy to secure the powder in a dry condition when employed in wet blasting. strips of thick and stron g paper or paper parchment in place of the tapes or threads above described. I make these strips narrower and wind them in narrower spirals than the enveloping material has been usually heretofore applied, and with these precautions experiment proves my single, double, or triple wound fuse, when correspondingly coated with varnish, to be more impervious to water than any correspondingly coated before known, and better In my invention I substitute y in other important respects than any other of like cost.

Experiments have been tried in coating fuses with rubber or other material more impervious than fuse-varnish with a view to render them perfectly water-tight; but this has'been found to be impraeticable, because 'the connement of the gases from the burning powder would accumulate pressure and .cause the fuse to.burst and burn unevenly. In my invention the employment of paper or paper parchment insures an efficient and flexible protection with liberty for the escape of gas through the spiral joint, which is presented at each half-inch,-or thereabout, and by making water-proof my inner tube, which directly incases the powder, by'coating it with rubber or other water-proof cement, a perfectly waterproof fuse may be secured without the objections due to similar outside coating, because in my invention, the rubber, being in close proximity to the powder,l is destoyed at once and allows the gasses to escape freely.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation by the aid of the drawings and of the letters of reference marked thereon.

Figure l is a cross-section of my central tube after thejute is wound on. Fig. 2 is a corresponding section of my fuse after the fuse-var nish is applied and a strip of paper or paper parchment has been wound on, Fig. 3, the same with another coat of varnish; Fig. 4, the same after another strip of paper or paper parch ment has been wound on, making what is called double-tapefuse,77 all on a scale greatly magnified. Fig. 5 is a section on a correspoi'idingly-magnified scale, showing at the upper end only the column of powder, and showing at successive lower stages first my inner tube, next my inclosing-rubber, next the fibers of jute, next the ordinaryslight bin ding-threads which serve to maintain the jute fibers in position while the fuse is awaiting subsequent operations, next the fuse-varnish, next the spirallywound external protection of paper, next the fuse-varnish again, Sie. Fig. 6 is an elevation, and Fig. 7 a section, of the funnel and certain of its connections, by which I prepare the inner tube and cover it with water-proof composition. Fig. 8 is a horizontal section on the line S S, showing the condition of the partially-formed tube at that point. Figs. 9, 10, and 11 show the condition of the inner tube at two different stages, Fig. 9 being a section on the line T T, and Fig. l0 a section on theline U U, Fig. ll, the same on V V. Fig. l2 is a section showing the material of theinner tube overlapped. This mode of construction may be in some cases preferable. Fig. 13 is a longitudinal section through my triple-tape fuse on a scale less magnified than Figs. l to 5. The rubber or other waterproof coating on the inner tube is tinted red, to more plainly distinguish it.

Similar letters of reference indicatelikeparts in all the figures.

I manufacture my fuses at two or more, distinct operations, lall analogous to those heretofore practiced.

A is the powder.

B is an inner tube which completely surrounds the powder, and which I prefer to make of dense and tough paper.

C is a water-proof and highly-adhesive composition which I prefer to make by dissolving raw india-rubber in oil of turpentinc or other volatile solvent.

D is a fibrous envelope, which I make, for economy, ofjute, and which is wound spirally around the parts A B C.

E is a slight spiral tie or confining-thread, which I prefer to triplicate or employ in the form of three separate spirals, of cotton or other slender parns.

Gis the fuse-varnish, which I prefer to make of wood-tar and coal-tar, of about equal proportions.

I'I is a spiral envelope, of paper or paper parchment. This latter I apply by means of the well-known winding machines, and after coating again with the fuse-varnish G, I apply at pleasure one or more additional coatings or envelopes of similar material, I and J. I apply a coat of the fuse-varnish G after each, and usually coat the whole with finelypulverized soapstone, whiting, or the like, (not representech) to render the su-rface less liable to be sticky. I apply the fuse-varnish G by dra-wing the material through the melted composition and stretching lit a considerable distance through the air on the way to the reel, so as to allow it to harden. The fibrous enveloping material D is applied by carrying it on bobbins around the descending contents in the manner described in the patent issued to my brother, Albert F. Andrews, dated July 28, 1857, and in another, No. 8,963, issued in 1852.

To manufacture and introduce my inner tube, B, and apply the rubber cement or other water-proof and adhesive cement thereon, I employ a funnel, L, and guide Z,` by the aid of which the strip of paper to form the said inner tube is curved gradually around into a tube, and the powder is inclosed therein in a continuous and smoothly-bounded line; andI employ a conveyer represented in a v ery primitive but effective form by the lower funnel, M, which contains a quantity of the soft cement and causes it to apply evenly and continuously over the whole exterior of the tube B as it emerges from the upperfunnel, L. Immediately below the lower funnel, M, the jute D is wound around, and succeeding this the binding-threads E are wound on, so as to confine and'protect the inner tube, as indicated.

Some of the advantages due to certain features of my invention may be separatety enui merated as follows:

First. By inclosing the powder A in an inner tube, B, as above described, a uniform line of powder is secured, and by coating the tube B with rubber or equivalentv cement, G, a perfectly water-proof fuse may be obtained, while the rubber coating, by being removed from the surface, precludes the liability of its being` eut or otherwise injured in tamping, and by its close proximity to the powder is certain to be immediately destroyed as the lire traverses along the fuse.

Second. By substituting paper or paper parchment for cloth or other material in the surfacing H, Src., of tape fuses, a fuse is produced of better quality and at less expense han heretofore known.

Vhat I claim as my invention, and desire to seeure by Letters Patent, is* V l. The inner tube, B, as herein described, and also the coating of the same with rubber or other equivalent material, for the purpose herein set forth.

2. The substituting of paper or paper parchment in the place of cloth or other material now used in the manufacture of tape fuses, substantially as herein described.

JOHN H. ANDREVS.

Vitnesses:

SAMUEL HADsELL, Aires XV. VooDFoRD. 

